inline int read(){    int x=0,f=1;char ch=getchar();    for(;!isdigit(ch);ch=getchar()) if(ch==‘-‘) f=-1;    for(;isdigit(ch);ch=getchar()) x=x*10+ch-‘0‘;    return x*f;}inline void write(int x){    if(x==0){putchar(‘0‘);return;}if(x<0)putchar(‘-‘),x=-x;    int len=0,buf[15];while(x)buf[len++]=x%10,x/=10;    for(int i=len-1;i>=0;i--)putchar(buf[i]+‘0‘);return;}